Flushing oil



Patented Mar. 9, 1954 FLiUsHINe 01 Mathew Kalinowski and Morris Feller, Chicago, Ill... assienors to. Standard Oil Company, Chicage, Ill., a; corporation of. Indiana No Drawing Application June 26, 1950, SerialNo. 170,468

This invention relates to improved solvents of the type generally referred to as flushing oils and: it-.pertains=more particularly to an improved method and means. for cleaning surfaces coated so-called varnish deposits, sludge, etc-., of thetype which isformedi for example in the crank cases of internal: combustion engines.

During the operation of internal combustion engines; (either spark ignition or compression ignition) with many types of'lubricating oil's, del posits; are formed on surfaces, particularly in the crank case of the engines, which should be removed from time to time in order to avoid excessivewear; plugging of oil channels, etc. There are seveial' kinds of deposits which accumulate on'suchsurfaces, such as sludge deposits which may be removed by high boiling aromatic solvents, lacquer or varnish deposits which are much harder to remove, and carbon deposits which are usually bonded bythe varnish deposits and when tend" to flake off when the varnish; deposits are removed. It is known that certain high boiling portions of the hydrocarbon product produced in the catalytiehydroforming of naphthe has beneficial properties for removing the sludge deposits (U'; S. 2,410,613) but at ordinary temperatures it is relatively ineffective for removing the lacquer or varnish deposits. Such solvents have been combined with alkylated' hydroformer polymer (U; S; 23913120) and phosphorous and sulfur-containing reaction products of olefin polymers of high molecular weight, (If. S. 2,495,030), these latter compositions being beneficial from the standpoint of preventing englne scoring when employed as crank case flush! ing oils without unduly interfering with solvent properties. object of our invention is to provide a flushing oil which has solvent properties superior to those obtainable in any Prior art com positions and which are particularly effective in removing internal combustion engine varnish deposits.

Whiie our improved solvent may be employed as a crankcase flushingoil in engine.v crank cases or lubricating systems per so (with or Without. addition of a lubricating: oil componentfor obtainine any desired viscosity) they are also val,- uable for cleaning; engine parts in repair shops... Such shops may simply maintain a bath of such solvent at ordinaryor elevated temperature and immerse in said bath for a period of a few minutes to several hours any metal parts which coritam sludge, varnish or other deposits caused by oxidation, polymerisation, etc. ofoil' on, said sur- LEMQS:

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We have discovered that the propane-insolu-i ble fraction of crude. fatty materials, which is obtained as. a residue in amounts of the order of about .2 to 2 or more Weight per cent when crude fats, fatty oils, or fatty acids, split. there: from are subjected to propane fractionation, is remarkably effective as a solvent for engine varnish. The propane-insoluble residues from propane fractionation of crude fatty materials contain most of the color bodies which were press-- ent in the crude materials and are so: dark-in color that they are referred to in commerce as ebony fats. The propane-insoluble residues from animal fats will be herein referred to' as ebony A and from vegetable fatty oils as ebony V. The properties of representative samples of ebony A and ebony V, respectively are approximately as follows (on a Water-free basis):

r pe y E ony A b n V Viscosity, Seconds Sayboltat 109 F. 6, 500 93Q Viscosity, Seconds Saybclt at 130 F f l, 860 430 Viscosity, Seconds Sa-ybolt at 210 F 300 100 Ash, weight percent u, 1.3 .06 IA. P. I. Gravity "degrees" 10 16 Acidity AS'PM- (D-664- Mg. KOBE gm 41; s3 Pentane Insoluble wcight percent, 2.6 4, 2 Benzene Insoluble, weight percent. 0.1- l 0 Saponification- Number. a... 190- 170 Percent Fatty Acid; 20 BL Iodine Number 58 106 The above p opert es. are, of cour e, me ely i1: Iustrative and it, should be. understood that oth, the amount, n properties. of. he ony fats w ll depend on the naturev of the crude fatty materi'al which issubiected; to propane fractionation art and is commonly referred to as the Solex-ol process currently in commercial use. A system for effecting such fractionation is described in considerable detail in U. S. 2,505,338. Forv most-J crude animal fats, vegetable oils and similar fatty materials (including fatty acids split from such fats and oils), the fractionation conditions are employed to give a propane-insoluble residue of a proximately 1%, ieabout. -2 o 2%. a though in some cases. such resins may be as large as 5% or even 10%.

While ebony fats per se are remarkably effective as engine varnish solvents, their effectiveness may be enormously augmented by adding thereto a high boiling mixture of poly methyl aromatics, polycyclic aromatics and methyl and poly methyl polycyclic aromatics of the type generally referred to in U. S. 2,410,613 and more specifically defined in U. S. 2,491,120 and 2,495,030. While hydroformer polymer" or bottoms is an excellent source of such high boiling aromatics, it should be understood, however, that these high boiling aromatics may be obtained as a neutral tar oil of similar boiling range and A. P. I. gravity obtainable from coal by-products. Another source of such high boiling aromatics is the catalytic cracking refractory stock as described in U. S. 2,335,596, although in the latter case the effectiveness of the high boiling aromatics may be improved by separating aliphatic components from the catalytic cracking refractory stock by extraction with, known solvents such as furfural, dimethyl formamide, and the like. Properties of the mixture of poly methyl aromatics, polycyclic aromatics and methyl and poly methyl polycyclic aromatics are as follows:

With respect to the boiling range, the end point should not exceed 650 F. and preferably should not exceed 625 F. in order that the solvent material may be free of condensed polycyclic aromatics of more than three rings and thus be safe from the point of view of possible carcinogenic properties. The solvent preferably has a point of approximately 400 F. and a 90% point in the range of about 500 to 550 F.

The following test data will illustrate the remarkable ffectiveness of ebony fats and particularly the combination of ebony fats with high boiling aromatics as hereinabove described. These tests were all made on materials coated with engine varnish by immersing the coated materials for a period of minutes in a bath of the respective solvent or solvent mixtur after which solvent was rinsed from the surfaces with a light naphtha. All of the test pieces had varnish coatings of substantially the same area and same type and quantity. The amount of varnish removal was determined visually.

R H Flash Pecerit Re mowiralilof a o 7 ng me am 5 Components By peolnt, O

Y 1'2, 210 F. W 01. O O C At 78 F. At 160 F.

Ebony V .e 560 100 60 Ebony V+aromatics- 9:1 275 60 70 75 Do. 5:5 205 80 85 1:9 200 29 30 30 165 0 i5 Ebony A" 560 300 50 65 Abony A-i-aromatics. 9:1 365 70 75 Do. 5:5 215 37 90 90 Do 1:9 195 29 50 S5 Aromatics. 165 0 l5 From the above data, it will be seen that the high boiling aromatic mixture per se (as taught in the prior art hereinabove referred to) is ineffective for removing engine varnish at 78 F. and is relatively ineffective for removing said engine varnish even at 160 F. (normal crank case operating temperatures). Even at the low temperature, the ebony compounds were two to three times as efiectiv for removing engine varnish as was the high boiling aromatic mixture at the high temperature. Obviously, due to their similarity in composition, ebony A and ebony V could be mixed with each other in any desired proportion, but it will be noted that the ebony A is markedly superior to ebony V in its solvent properties for engine varnish.

Perhaps the most surprising result shown by the above data is the fact that the mixtures of the ebony fats with the high boiling aromatic mixtures produce results which are not cumulative or additive but which are highly synergistic. For example, ebony V at 78 F. removes only 30% of the engine varnish. Adding 10 volume per cent of high boiling aromatics (per se ineffective at this temperature) raises the effectiveness of ebony V to Adding 50% of said aromatics raises the effectiveness of ebony V to 80%. Adding as little as 10% of ebony V to said aromatics gave 30% varnish removal. Similar synergistic effects are found in the ebony A-aromatics mixtures, the ebony A being somewhat more effective for engine varnish removal. For optimum varnish removal both the ebony fat and high boiling aromatic should be present in large proportions. By admixing the defined aromatic mixture with ebony fats, varnish removal can be efiected at ordinary room temperatures and there is no longer any necessity of maintaining such a bath at 160 F. or of keeping the motor running during a flushing operation in order to maintain this high temperature level. However, use of our flushing oils in a running engine is advantageous since it insures circulation and intimate contact of the flushing oil with the parts to be cleaned.

The above data also show that the inclusion of as little as 10% of ebony fat to high boiling aromatics raises the flash point by as much as 30 to 35 F. The 50-50 mixture of ebony A with high boiling aromatics has a flash point of 215 F. Also, the viscosity of the substantially non-viscous aromatics is markedly raised by as little as 10% of ebony fat. Another attribute of the combination of ebony fat with the defined aromatic mixture is the effectiveness of the ebony fat in peptizing the sludge components so that they may be held in suspension in the aromatic mixture, thus markedly improving the latter with respect to its previously known functions.

Our mixtures of ebony fat and high boiling aromatics were also tested for cleaning varnish from varnish-coated engine pistons by dipping the pistons 5 to 15 times in a bath of the flushing oil composition maintained at a temperature of F. with suiiicient time between dips to permit drainage of excess flushing oil from the piston followed by a soaking period of about 15 minutes. Here again, the optimum solvent was one containing substantially equal parts by volume of ebony A and high boiling aromatics with mixtures preponderating in the ebony fat giving results superior to mixtures preponderating in aromatics. With the 50-50 mixture of ebony A and high boiling aromatics, it was noted that the varnish on the pistons had softened after the first dip. After the soaking period of 15 minutes followed by wiping off the flushing oil with a cloth, the piston was cleaned of all varnish deposit. In a varnish rating test, wherein an average fouled piston has a rating of 5 and a completely clean piston has a rating of 10, the high boiling aromatics alone had no effect on the varnish rating after 5 dips at 140 F., while our 50-50 ebony A mixture improved the varnish rating from 5 to '7. After 15 dips the aromatics alone resulted in a varnish rating of only 5.5 while the 50-50 ebony A mixture produced a varnish rating of 8.5. A 15 minute soaking period at 140 F. followed by wiping or rinsing ofi the soaked surfaces is usually employed to effect removal of piston varnish.

It is the ebony fat and/or the ebony fat in combination with the defined aromatic solvent mixture which constitutes our improved solvent but it should be understood that our solvent may be diluted with a hydrocarbon oil for increasing or decreasing its viscosity particularly when it is employed in place of the usual lubricant for flushing out a lubricating system. Other known flushing oil additives may likewise be employed in addition to the essential component or components of our solvent. After a purging or solvent treatment of a varnish coated surface, it is usually desirable (but not always necessary) to rinse off residual solvent by means of a light hydrocarbon oil or other suitable rinsing liquid.

Having thus described our invention and preferred embodiments thereof, what we claim is:

1. The method of cleaning surfaces coated with internal combustion engine varnish deposits and sludge which method comprises washing said surfaces with a material produced as an approximately 1% to 2% propane-insoluble residue when a crude fatty material is extracted with propane.

2. The method of claim 1 wherein the crude fatty material is an animal fat.

3. The method of claim 1 wherein the crude fatty material is a vegetable oil.

4. The method of claim 1 wherein the crude fatty material is a crude fatty acid split from a crude fatty acid glyceride.

5. The method of claim 1 in which at least 2 volume per cent of the material is admixed with a fraction of aromatics boiling in the range of 350-650 F. and having an A. P. I. gravity in the range of to 20, said fraction containing substantial amounts of poly methyl benzenes, poly- 60 23951030 cyclic hydrocarbons and mono and poly methyl polycyclic aromatic hydrocarbons.

6. A flushing oil which comprises a mixture of aromatics boiling in the range of 350 to 650 F., said mixture having an A. P. I. gravity in the range of 10 to 20 and consisting chiefly of poly methyl benzene, polycyclic aromatics and mono methyl and poly methyl polycyclic aromatics in combination with at least about 2 volume per cent of a propane-insoluble residue of a crude fatty material, which residue constitutes only about .1 to 2% of said crude fatty material.

7. The flushing oil of claim 6 wherein the crude fatty material is an animal fat.

8. The flushing oil of claim 6 wherein the crude fatty material is a vegetable oil.

9. The flushing oil of claim 6 wherein the crude fatty material is a fatty acid split from a crude fatty acid glyceride.

10. A flushing oil which consists essentially of about 2% to 98% by volume of an aromatic solvent boiling in the range of 350 to 650 F., having an A. P. I. gravity in the range of 10 to 20, and consisting chiefly of poly methyl benzene, polycyclic aromatics and mono methyl and poly methyl polycyclic aromatics in combination with about 98% to 2% by volume of an ebony fat, which ebony fat is a propane-insoluble residue of a crude fatty material, which residue constitutes only about .1 to 2% of said crude fatty material.

11. A flushing oil which comprises about to volume percent of an aromatic solvent boiling in the range of 350 to 650 F., having an A. P. I. gravity in the range of 10 to 20, and consisting chiefly of poly methyl benzene, polycyclic aromatics and mono methyl and poly methyl polycyclic aromatics in combination with about 10 to 50 volume percent of an ebony fat which ebony fat is a propane-insoluble residue of a crude fatty material, which residue constitutes only about .1 to 2% of said crude fatty material.

MATHEW L. KALINOWSKI. MORRIS FELLER.

References Cited in the file of this patent UNITED STATES PATENTS Name Date Starrett Jan. 17, 1950 Number 

10. A FLUSHING OIL WHICH CONSISTS ESSENTIALLY OF ABOUT 2% TO 98% BY VOLUME OF AN AROMATIC SOLVENT BOILING IN THE RANGE OF 350* TO 650* F., HAVING AN A.P.I. GRAVITY IN THE RANGE OF 10* TO 20*, AND CONSISTING CHIEFLY OF POLY METHYL BENZENE, POLYCYCLIC AROMATICS AND MONO METHYL AND POLY METHYL POLYCYCLIC AROMATICS IN COMBINATION WITH ABOUT 98% TO 2% BY VOLUME OF AN "EBONY FAT," WHICH "EBONY FAT" IS A PROPANE-INSOLUBLE RESIDUE OF A CRUDE FATTY MATERIAL, WHICH RESIDUE CONSTITUTES ONLY ABOUT .1 TO 2% OF SAID CRUDE FATTY MATERIAL. 